Speed regulator for phonographs



Nov. 26, 1929. v. JAKOB Filed Oct. 11, 1926 SPEED REGULATOR FOR PHONOGRAPHS MEEQ Patented Nov. 26, 1929 VICTOR JAKOB, OF RACINE, WISCONSIN SPEED REGULATOR FOR PHONOGRAPHS Application filed October 11, 1926. Serial No. 140,913.

This invention relates to speed regulators for phonographs.

In phonographs of the usual type, it is the customary practice to rotate the record carrying table at a constant speed, although the linear travel of the stylus is greater at the outer periphery of the record than at its inner periphery. The result of this construction is that the outer portion of the record travels very much faster than is required and, consequently, the length of the record is unnecessarily shortened.

Objects of this invention are to provide anovel form of mechanism for driving the table of a phonograph so that the travel of the record with respect to the stylus is at the same rate at the outer periphery of the record as at the inner periphery of the record or, in other words, to provide means which grad- 2o ually varies the speed of rotation of the table,

as the stylus shifts its radial position with respect to the center of the table, so that the linear speed is at all times constant.

In view of the fact that nearly all records I as now made are adapted for use on phonographs in which the table rotates at a constant speed, this invention has for its further object the provision of means for quickly changing the mechanism over from that preso viously described, into one in which the table is rotated at a constant predetermined number of revolutions per minute, and the automatic varying of the speed is temporarily dispensed with. Further objects are to provide a mechanism having the characteristics stated above in which the construction is very simple and practical and may be readily produced and easily operated.

An embodiment of the invention is shown in the acompanying drawings in which Figure 1 is a plan view partly in section and partly broken away showing the essential portions of the mechanism for securing the variable rate of rotation for the table;

Figure 2 is a sectional elevation approximately on the line 22 of Figure 1, the table and the control mechanism, however, being shown in full lines;

Figure 3 is a side elevation with parts having the usual stylus 4t.

The drive for the table is extremely simple and novel in construction, as will be apparent as the description proceeds. It comprises a driving roller or drum 5 operated or driven by a motor 6, such drum and motor being carried by a pivoted frame 7, the frame be ing pivoted upon the uprights 8. The free end of the frame is provided with a guiding pin 9, as shown most clearly in Figure 2, and

a spring 10 loosely surrounds the pin and carries the weight of the frame and associated parts, washers being preferably pro vided at the upper and lower ends of the spring. It is to be noted particularly from Figures 1 and 2 that a cam shift member 11 is pivoted at 12, and is provided with a controlling lever 13. This cam shift member is provided with a curved slot 14}c which loosely receives the pin 9. It is to be noted from Figures 2 and 3 that one end of the cam shift member is raised and the other end lowcred, so that as it is rocked about its pivot point, it raises the frame upwardly into operative position for driving, or lowers it out of driving position.

The roller 5 or drum carries a rubber ring 15 which is of greater internal diameter than the roller, as may be seen fom Figure 2. This rubber ring operatively connects the constantspeed drum 5 with the lower side of the revoluble table 1.

It is to be noted that the ring 15 may be freely shifted along the drum and means in the form of a lever 16 is'provided for shifting this ring, the lever being equipped with 9 spaced fingers or forked ends 17 and 17 above and below the drum which loosely engage the ring. This lever is operated by means of the tone arm through the medium of a lever 18 rigid with the tone arm and a connecting link 19, as may be seen from Figure 1. 7

It is to be noted that the construction is extremely simple and may be easily produced. For example, the spindle 20 for the table 1, as shown in Figure 1, may be carried by a bracket 21 and may rest at its lower end upon a bearing pin 22. Further, the lever 16, as may be seen from Figure 2, can easily be carried by a similar bracket 23. However, it is merely necessary to loosely pivot=the shaft 2 1 of the lever 16 within the upper and lower ends of the bracket 23. provided with an upper aperture into which the end of the link 19 may be hooked, as

shown in Figure 1, under conditionsdescribed in detail hereinafter.

' The operation of the apparatus is as follows:

When it is desired to play a record in which the linear speed of'the record passing the stylus is to be maintained as, for instance, for a record intended for uniform linear speed of the groove pastthe stylus of a reproducer, it is merely necessary to rock the con trollinglever 13 into the position shown-in Figure 1. This raises the pivoted frame 7 andyieldinglypresses the ring 15 into contact with-the underside of the table 1, and

consequently. operatively connects the drunr and the table. Thereafter, motion of the tone arm2 in following the record is transmitted to the lever 16, and gradually rocks the lever inwardly, thus moving the ring 15 nearer. the

center of the rotary table and, consequently,

keeping the ring substantially directly under the stylus at all times, and maintaining the linear rate of travel absolutely constant;

If it is desired to play an'ordinary type of record, it ismerely, necessary to unhook the link 19 from the lever 18 and hook it'in the bracket 19*.

lines in Figure 1.

speed. 7

From actual experiments,it has been found.

that the driving mechanism for the table requires a minimum amount of eflortto shift the ring 15, and, consequently,suchconstruction has been found highly practical and easily controlled from the tone arm.

It will be seen ithata novel formof pl1ono-- graph has been provided which will play records either; with a constant linear speed,

or else with a variable linear speed'as' has most easily controlled, and offers extremely low frictional resistance.

Further, it'will betseen that'the mechanismmay be: easily produced by ordinary machine shop methods and that it is 'reliable and sub-- stantially free: from fragileparts.

A bracket 19 is This rocks the control lever-or handle 13 into the positionshown indotted', This will cause the phono-' graph record to be driven at its highest- The term phonograph as used in the appended claims is intended to include both the reproducing andthe recording machines of this general type.

Although the invention has been described in considerable detail, such description is intended as illustrative rather than limiting as the invention may be variously embodied and as the scope of such invention is to be determined'as claimed.

1. Driving mechanism comprising a disc, a'drummounted below said disc and'having its axis at right angles to the axis of the disc,

a friction ring loosely surrounding said drum and adapted to contact with said disc, means for raising or lowering said drum to cause saidring to contact with or move away from said disc, and means for moving said ring towards or away from the center ofsaid disc, whereby the speed of rotation of said disc may be varied.

2. Driving mechanismcomprising a disc, a drum mounted below saiddisc and'havin'g its axis at right angles to the axis of the disc, a friction ring loosely surrounding said drum and adapted to contact with said disc, a forked lever havingits ends rounded and receiving portion of said ring immediately in front o't'the point oit'contactof'said ring. and saidfdisc and'on the leading side of said disc, and means for moving said lever, whereby said ring bodily pivots about its point of contact during shitting. g

3. Driving mechanism comprising a disc a'drum mounted'below saiddisc and havingits axis at right angles to the axis ofthe disc, a friction ring loosely surrounding said drum and adapted to contact with said disc, a forked lever having its-ends rounded and receiving a portion o'fsaidfring immediately in front of the point of contact of said ringandsaid disc and on .the leading side of said disc, and means for moving said lever, whereby said-ring bodily pivots about its point ofcontactduring shifting, said'ring being formed otrubber.

In testimony that I claim theforegoing' I have hereunto set'my hand at-Milwaukee, in the county of Milwaukee and State of YVisconsin.

VICTOR J AKOB. 

